Knee-action street sweeper broom



March 3, 1959 Filed June 7, 1956 H. EURGDORFF KNEE-ACTION STREET SWEEFER BROOM 2 Sheets-Sheet 1 a E :l

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United States Patent KNEE-ACTION STREET SWEEPER BROOM Henry Burgdoflf, Long Beach, Calif. Application June 7, 1955, Serial No. 590,014 sclaims. 01. 15-84) This invention relates, generally to truck-type street sweepers which employ a large power driven cylindrical broom, transversely disposed with respect to the street sweeper', to whisk refuse from the street into the street sweeper, usually by way of an elevator means which transports the refuse from the pickup broom to a refuse hopper. More particularly, the present invention relates to a novelarrangement for carrying the pickup broom between pair of arms each capable of swiveling about one end and of longitudinal rotation topermit said pick- .up broom to adjust to the; contour ofthe street surface.

.In' street sweepers heretofore known, it hasbeen'customary to employ a large cylindrical broom transversely mounted at the rearof the street sweeper and rotated by meansof a power tahe oif from the street sweeper engine, to pick up refuse from the street. It has been customary to carry the broom on bearings mounted in a frame swinging about a transverse horizontal axis at the rear ofthe street sweeper. Springs, or other yielding support for the frame have been used to carry the broom in light brushing contact with the street surface. Most of the weightof the broom is thus carried bythe street sweeper rather'jthan by thebroom bristles, thus avoiding unnecessary powerconsumption andbristle wear.

However, the "great majority of paved roads are more or less crowned in the center, so that a street sweeper travelling down the right side of a crowned street subjects its pickup broom to" very heavy wear near its left end, until the stamina-been worn .down to the shape of frustum. of a cone. Even then, excessive wear is encounteredes the street sweeper changes from streets ha n on e. .sweep arelatively flat surface.

The same forceswhich weardown the broom by hearing unequally across its transverse dimension, also subject the supporting. framework towbending stresses, which are sometimes severe enough to be felt by the street sweeper operator as a jolting of the entire apparatus.

It is a major object of the present invention to provide a street sweeper pickup broom with knee-action suspension, that is with each end of the broom axis sulficiently free to move to permit any lateral rocking of the broom required for adjustment to inclinations of the road surface transverse to the direction of travel of the street sweeper.

It is another major object of the invention to provide broom driving motor means riding with the broom itself and free to move relative to the street sweeper, without any mechanical driving interconnection therewith.

It is another object of the present invention to provide a knee-action suspension with means for adjusting the looseness of fit of movable joints in the suspension, to permit twisting accommodation of the suspension without bending of its structural members.

Still other objects of the invention, and advantages thereof, will be apparent from the following description,

taken in connection with the accompanying drawings, in which:

1e of crown to another, or attempts to 2,875,459 Patented Mar. 3, 1959 Figure 1 is a right side elevation of the rear part of a truck-type street sweeper; f

Figure 2 is a left side elevation of the rear part of a street sweeper;

Figure 3 is a plan view of a pickup brush mounted in a street sweeper with a form of the knee-action suspension of the present invention;

Figure 4- is a rear elevation of the suspension of Figure 3 t Figure 5 is a view taken from the same direction as Figure 4 but showing the accommodation of the broom and suspension to a street surface of opposite slope;

Figure 6 is a fragmentary section detailed view of the suspension mounting on the street swee er; and

Figure 7 is a detail of the broom mounting;

In Figure l, a street sweeper is indicated generally by the numeral 10, only the rear part of the sweeper, particularly those associated with a pickup broom being illustrated.

The rear part of the street sweeper chassis 11 is supported on the rear wheels'lZ and carries a street sweeper body 13, the interior of which (not shown) serves at least in part as a refuse receiving hopper;

A large cylindrical pickup broom 14 is transversely disposed at the rear of the streetsweeper 10 and carried in combination with a pickup assembly indicated generally by the numeral 15- and including ahousin'g 16 for a chute and elevator means (not shown) for transporting refuse swept up by the pickup broom to the refuse hopper within sweeper body 13. i

Broombearings 1-7 and 18 (see Figure 2-) at each end of the broom axis 19 are carried at the swinging end of a pair of supporting arms 20 and 21, which are swivel connected to the chassis 11 at 22- and 23 respectively. A

picku broom and bond 24, side shoes 25, andarms 20 and 2'1,-can be a raised from the street surface, together with the broom chain- 28.

When it is desiredto dump refuse fromthe hopper within the sweeper body 13, the hydraulic cylinder 29 (seen in the left side view of Figure 2) is actuated to expel its plunger and thereby lift the assembly including the broom 14, hopper 24,- shoes 25, and supporting ar'r'ns 206116 2 1, and also to retract the lower part of thechute 30, thereby unlatching hopper gate latch 31 and opening the hopper gate 32 by means of the rod 33*. i

Hydraulic motor means are used to drive each part ofthe street sweeper10 independently of the others. A hydraulic rnotor34", supplied with hydraulie'fluid through lines 35, is used to drive the streefsweeper elevator system (not shown) and a hydraulic motor 36, supplied with hydraulic fluid through lines 37, mounted on supporting arm 21, drives the pickup brush 14. Note that the hydraulic motor 36 rides with the pickup brush assembly and is connected to the street sweeper body 13 only by flexible hydraulic conduits, so that complex mechanical driving means are avoided, and assembly and disassembly is relatively simple.

Each of the brush-supporting arms 20 and 21 is suspended near its midpoint from brackets 38 and 39 on the street sweeper body 13 by means of helical springs 40 and 41, respectively. The springs 40 and 41 are anchored to the arms 20 and 21 by means of nuts 42 and 43, and crank screws 44 and 45, to provide anchorage points which are longitudinally adjustable along the sup porting arms. Ordinarily, the left side spring 41 is anchored at a point nearer the pickup broom than the right side spring 40, so that the transverse position of the broom 14 matches the usual contour of the street surface as the street sweeper 10 moves down the right side.

As best seen in the Figures 3, 4, and 5, the supporting arms 20 and 21 are each comprised of two sections, 20a

and 20b, and 21a and 21b, respectively, which are rotatable relative to each other about the longitudinal axis of the arm which they comprise. Thus, a first section ,201; islcoupled to a section 20b by means of atubular coupling 200 which combines the first and second sections 20:; and 20b into a single beam arm 20 butpermits free rotation of the second section 20b about a longitu- ,dinal axis while the first section 20a experiences no rotation. The left-side arm 21 is similarly provided with a coupling 21c.

. The: first section-20a of the arm 20 is swiveled at the truck chassis 11 by means of a transverse tubular bearing '46, welded at-the pivot end of the first section 20a, and received on a stub shaft 47, seating against a shoulder 48 thereon, and retained by a cap 49 threaded into the end .of the stub shaft 47 as indicatedat 50. The left arm 21 is similarly swiveled. I g

As seen in Figure 3, the tubular bearing 46 is longitudinally split, at 51 and provided with a pair of cars 52, through which a tightening screw 53 is passed to provide. means for loosening or tightening the play in the swivel connection.

- The second section 20b, the bearing supporting section of the arm 20is shownin detail in Figure 7. A hearing plate 54 is welded to the end of the second section 20b .of opposite contour by lateral rocking of several degrees.

An important feature of the invention is that the hydraulic driving means36 is associated with a safety hydraulic by-pass line, preferably at the pump (not shown) supplying hydraulic fluid under pressure. Thus, in ,case the pickup broom 14 is jammed by refuse or the street surface, the pressure in the hydraulic system grows until the by-pass valve opens, which pressure is established at some point lower than that at which structural damage could occur to the street sweeper. It will be understood that the specific embodiment above described is exemplary only of the invention and not limitative. It is my intention to include within the scopeof my invention all those variations, modifications, and improvements which fall within the scope of the appended claims.

I claim:

I 1. In a street sweeper, a pickup broom for projecting refuse from the street surface into said street sweeper, which includes: a cylindrical broom; a pair of bearings rotatably supporting said broom at each endof its axis; a pair of arms, one at each end 'of said broom, each carrying one of said bearings near one end and swivela-bly attached to said street sweeper at the other end each of said arms having means therein permitting rotation of the bearing end of said arm relative to the swivelably attached end about the longitudinal axis of said arm, and resilient supporting means between said street sweeper and each of said arms to supportv said broom in sweeping contact with the street surface.

2. A pickup broom as described in claim 1 which is driven by means of a hydraulic motor carried on one of said supporting arms, and suppliedwith' hydraulic fluid by means of flexible connections with said street sweeper.

3. In a street sweeper, a pickup broom for projecting refuse from the street surface into said street sweeper, which includes: a cylindrical broom; a pair of bearings rotatably supporting said broom at each end of its axis; a pair of arms, one on each side ofsaid street sweeper, each of said arms being swivelably attached to said street sweeper; a pair of bearing carrying means, one with each of said bearings attached to the swinging end of each of said arms by means of a coupling permitting relative rotation between said means and said arm about the longitudinal axis of said arm; motor means associated with one of said bearing carrying means for driving said broom; and resilient support means between said street sweeper and each of said arms.

4. A street sweeper as described in claim 3 which said swivelable attachment includes: shaft means projecting from each side of said street sweeper; cylindrical hearing means on the swivelable attached end of each of said arms and received on said shaft means, said cylindrical bearing means being longitudinally split and adjustable to increase or reduce play.

5. A street sweeper as described in claim 3 in which each of, said bearing carrying means includes a vertically disposed plate with a horizontal slot to receive a broom bearing and which said resilient support means includes .a spring suspension from said street sweeper, on each arm, and anchoring means on each arm for said spring suspension which is longitudinally adjustable along said arm.

References Cited in the file of this patent Great Britain Mar. 24, 19 5 4 

